CCNPv7 ROUTE lab2 1 EIGRP load balancing instructor

CCNPv7 ROUTE Chapter Lab 2-1, EIGRP Load Balancing Instructor Version Topology Objectives • Review a basic EIGRP configuration • Explore the EIGRP topology table • Identify successors, feasible successors, and feasible distances • Use show and debug commands for the EIGRP topology table • Configure and verify equal-cost load balancing with EIGRP • Configure and verify unequal-cost load balancing with EIGRP Background As a senior network engineer, you are considering deploying EIGRP in your corporation and want to evaluate its ability to converge quickly in a changing environment You are also interested in equal-cost and unequal-cost load balancing because your network contains redundant links These links are not often used by other link-state routing protocols because of high metrics Because you are interested in testing the EIGRP claims that you have read about, you decide to implement and test on a set of three lab routers before deploying EIGRP throughout your corporate network © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing Note: This lab uses Cisco 1941 routers with Cisco IOS Release 15.4 with IP Base Depending on the Cisco IOS Software version, the commands available and output produced might vary from what is shown in this lab Required Resources • routers (Cisco IOS Release 15.2 or comparable) • Serial and Ethernet cables Step 0: Suggested starting configurations a Apply the following configuration to each router along with the appropriate hostname The exec-timeout 0 command should only be used in a lab environment Router(config)# no ip domain-lookup Router(config)# line Router(config-line)# logging synchronous Router(config-line)# exec-timeout 0 Step 1: Configure the addressing and serial links b Create three loopback interfaces on each router and address them as 10.1.X.1/30, 10.1.X.5/30, and 10.1.X.9/30, where X is the number of the router Use the following table or the initial configurations located at the end of the lab Router Interface IP Address/Mask R1 Loopback11 10.1.1.1/30 R1 Loopback15 10.1.1.5/30 R1 Loopback19 10.1.1.9/30 R2 Loopback21 10.1.2.1/30 R2 Loopback25 10.1.2.5/30 R2 Loopback29 10.1.2.9/30 R3 Loopback31 10.1.3.1/30 R3 Loopback35 10.1.3.5/30 R3 Loopback39 10.1.3.9/30 R1(config)# interface Loopback 11 R1(config-if)# ip address 10.1.1.1 255.255.255.252 R1(config-if)# exit R1(config)# interface Loopback 15 R1(config-if)# ip address 10.1.1.5 255.255.255.252 R1(config-if)# exit R1(config)# interface Loopback 19 R1(config-if)# ip address 10.1.1.9 255.255.255.252 R1(config-if)# exit R2(config)# interface Loopback 21 R2(config-if)# ip address 10.1.2.1 255.255.255.252 R2(config-if)# exit R2(config)# interface Loopback 25 R2(config-if)# ip address 10.1.2.5 255.255.255.252 R2(config-if)# exit © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing R2(config)# interface Loopback 29 R2(config-if)# ip address 10.1.2.9 255.255.255.252 R2(config-if)# exit R3(config)# interface Loopback 31 R3(config-if)# ip address 10.1.3.1 255.255.255.252 R3(config-if)# exit R3(config)# interface Loopback 35 R3(config-if)# ip address 10.1.3.5 255.255.255.252 R3(config-if)# exit R3(config)# interface Loopback 39 R3(config-if)# ip address 10.1.3.9 255.255.255.252 R3(config-if)# exit c Specify the addresses of the serial interfaces as shown in the topology diagram Set the clock rate to 64 kb/s, and manually configure the interface bandwidth to 64 kb/s Note: If you have WIC-2A/S serial interfaces, the maximum clock rate is 128 kb/s If you have WIC-2T serial interfaces, the maximum clock rate is much higher (2.048 Mb/s or higher depending on the hardware), which is more representative of a modern network WAN link However, this lab uses 64 kb/s and 128 kb/s settings R1(config)# interface Serial 0/0/0 R1(config-if)# description R1 >R2 R1(config-if)# clock rate 64000 R1(config-if)# bandwidth 64 R1(config-if)# ip address 10.1.102.1 255.255.255.248 R1(config-if)# no shutdown R1(config-if)# exit R1(config)# interface Serial 0/0/1 R1(config-if)# description R1 >R3 R1(config-if)# bandwidth 64 R1(config-if)# ip address 10.1.103.1 255.255.255.248 R1(config-if)# no shutdown R1(config-if)# exit R2(config)# interface Serial 0/0/0 R2(config-if)# description R2 >R1 R2(config-if)# bandwidth 64 R2(config-if)# ip address 10.1.102.2 255.255.255.248 R2(config-if)# no shutdown R2(config-if)# exit R2(config)# interface Serial 0/0/1 R2(config-if)# description R2 >R3 R2(config-if)# clock rate 64000 R2(config-if)# bandwidth 64 R2(config-if)# ip address 10.1.203.2 255.255.255.248 R2(config-if)# no shutdown R2(config-if)# exit R3(config)# interface Serial 0/0/0 R3(config-if)# description R3 >R1 R3(config-if)# clock rate 64000 R3(config-if)# bandwidth 64 R3(config-if)# ip address 10.1.103.3 255.255.255.248 R3(config-if)# no shutdown R3(config-if)# exit R3(config)# interface Serial 0/0/1 R3(config-if)# description R3 >R2 R3(config-if)# bandwidth 64 © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing R3(config-if)# ip address 10.1.203.3 255.255.255.248 R3(config-if)# no shutdown R3(config-if)# exit d Verify connectivity by pinging across each of the local networks connected to each router e Issue the show interfaces description command on each router This command displays a brief listing of the interfaces, their status, and a description (if a description is configured) Router R1 is shown as an example R1# show interfaces description Interface Status Em0/0 admin down Gi0/0 admin down Gi0/1 admin down Se0/0/0 up Se0/0/1 up Lo11 up Lo15 up Lo19 up R1# f Protocol Description down down down up R1 >R2 up R1 >R3 up up up Issue the show protocols command on each router This command displays a brief listing of the interfaces, their status, and the IP address and subnet mask configured (in prefix format /xx) for each interface Router R1 is shown as an example R1# show protocols Global values: Internet Protocol routing is enabled Embedded-Service-Engine0/0 is administratively down, line protocol is down GigabitEthernet0/0 is administratively down, line protocol is down GigabitEthernet0/1 is administratively down, line protocol is down Serial0/0/0 is up, line protocol is up Internet address is 10.1.102.1/29 Serial0/0/1 is up, line protocol is up Internet address is 10.1.103.1/29 Loopback11 is up, line protocol is up Internet address is 10.1.1.1/30 Loopback15 is up, line protocol is up Internet address is 10.1.1.5/30 Loopback19 is up, line protocol is up Internet address is 10.1.1.9/30 R1# Step 2: Configure EIGRP a Enable EIGRP AS 100 for all interfaces on R1 and R2 using the commands Do not enable EIGRP yet on R3 For your reference, these are the commands which can be used: R1(config)# router eigrp 100 R1(config-router)# network 10.0.0.0 R2(config)# router eigrp 100 R2(config-router)# network 10.0.0.0 b Use the debug ip routing and the debug ip eigrp 100 commands to watch EIGRP install the routes in the routing table when your routers become adjacent (Note: The type of output you receive may vary depending upon the IOS.) You get output similar to the following R3# debug ip routing © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing IP routing debugging is on R3# debug ip eigrp 100 R3# conf t Enter configuration commands, one per line End with CNTL/Z R3(config)# router eigrp 100 *Jun 22 11:06:09.315: RT: add router 2048, all protocols have local database R3(config-router)# network 10.0.0.0 *Jun 22 11:06:18.591: %DUAL-5-NBRCHANGE: EIGRP-IPv4 100: Neighbor 10.1.103.1 (Serial0/0/0) is up: new adjacency *Jun 22 11:06:18.591: %DUAL-5-NBRCHANGE: EIGRP-IPv4 100: Neighbor 10.1.203.2 (Serial0/0/1) is up: new adjacency *Jun 22 11:06:19.055: RT: updating eigrp 10.1.102.0/29 (0x0) : via 10.1.103.1 Se0/0/0 1048578 *Jun 22 11:06:19.055: RT: add 10.1.102.0/29 via 10.1.103.1, eigrp metric [90/41024000] *Jun 22 11:06:19.055: RT: updating eigrp 10.1.1.0/30 (0x0) : via 10.1.103.1 Se0/0/0 R3(config-router)#end 1048578 *Jun 22 11:06:19.055: RT: add 10.1.1.0/30 via 10.1.103.1, eigrp metric [90/40640000] *Jun 22 11:06:19.055: RT: updating eigrp 10.1.1.4/30 (0x0) : via 10.1.103.1 Se0/0/0 1048578 *Jun 22 11:06:19.055: RT: add 10.1.1.4/30 via 10.1.103.1, eigrp metric [90/40640000] *Jun 22 11:06:19.055: RT: updating eigrp 10.1.1.8/30 (0x0) : via 10.1.103.1 Se0/0/0 1048578 *Jun 22 11:06:19.055: RT: add 10.1.1.8/30 via 10.1.103.1, eigrp metric [90/40640000] *Jun 22 11:06:19.059: RT: updating eigrp 10.1.2.0/30 (0x0) : via 10.1.103.1 Se0/0/0 1048578 *Jun 22 11:06:19.059: RT: add 10.1.2.0/30 via 10.1.103.1, eigrp metric [90/41152000] *Jun 22 11:06:19.059: RT: updating eigrp 10.1.2.4/30 (0x0) : via 10.1.103.1 Se0/0/0 1048578 R3# R3(config-router)# end R3# R3#undebug all All possible debugging has been turned off R3# Essentially, the EIGRP DUAL state machine has just computed the topology table for these routes and installed them in the routing table c Check to see that these routes exist in the routing table with the show ip route command R3# show ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing E1 - OSPF external type 1, E2 - OSPF external type i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP a - application route + - replicated route, % - next hop override Gateway of last resort is not set D D D D D D C L C L C L D C L C L R3# 10.0.0.0/8 is variably subnetted, 17 subnets, masks 10.1.1.0/30 [90/40640000] via 10.1.103.1, 00:10:54, Serial0/0/0 10.1.1.4/30 [90/40640000] via 10.1.103.1, 00:10:54, Serial0/0/0 10.1.1.8/30 [90/40640000] via 10.1.103.1, 00:10:54, Serial0/0/0 10.1.2.0/30 [90/40640000] via 10.1.203.2, 00:10:54, Serial0/0/1 10.1.2.4/30 [90/40640000] via 10.1.203.2, 00:10:54, Serial0/0/1 10.1.2.8/30 [90/40640000] via 10.1.203.2, 00:10:54, Serial0/0/1 10.1.3.0/30 is directly connected, Loopback31 10.1.3.1/32 is directly connected, Loopback31 10.1.3.4/30 is directly connected, Loopback35 10.1.3.5/32 is directly connected, Loopback35 10.1.3.8/30 is directly connected, Loopback39 10.1.3.9/32 is directly connected, Loopback39 10.1.102.0/29 [90/41024000] via 10.1.203.2, 00:10:54, Serial0/0/1 [90/41024000] via 10.1.103.1, 00:10:54, Serial0/0/0 10.1.103.0/29 is directly connected, Serial0/0/0 10.1.103.3/32 is directly connected, Serial0/0/0 10.1.203.0/29 is directly connected, Serial0/0/1 10.1.203.3/32 is directly connected, Serial0/0/1 d After you have full adjacency between the routers, ping all the remote loopbacks to ensure full connectivity You should receive ICMP echo replies for each address pinged e Verify the EIGRP neighbor relationships with the show ip eigrp neighbors command R1# show ip eigrp neighbors EIGRP-IPv4 Neighbors for AS(100) H Address Interface 10.1.103.3 10.1.102.2 R1# Se0/0/1 Se0/0/0 R2# show ip eigrp neighbors EIGRP-IPv4 Neighbors for AS(100) H Address Interface 10.1.203.3 10.1.102.1 R2# Se0/0/1 Se0/0/0 R3# show ip eigrp neighbors EIGRP-IPv4 Neighbors for AS(100) H Address Interface 10.1.203.2 10.1.103.1 Se0/0/1 Se0/0/0 © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Hold Uptime SRTT (sec) (ms) 13 00:14:20 49 10 00:29:14 37 Hold Uptime SRTT (sec) (ms) 13 00:14:28 71 13 00:29:21 35 Hold Uptime SRTT (sec) (ms) 13 00:14:07 1305 14 00:14:07 42 RTO Q Cnt 2340 2340 Seq Num 36 RTO Seq Num 36 RTO Seq Num 37 37 Q Cnt 2340 2340 Q Cnt 5000 2340 Page of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing R3# Step 3: Examine the EIGRP topology table a EIGRP builds a topology table containing all successor routes The course content covered the vocabulary for EIGRP routes in the topology table What is the feasible distance of route 10.1.1.0/30 in the R3 topology table in the following output? The feasible distance (FD) for the 10.1.1.0/30 route is 40640000 R3# show ip eigrp topology EIGRP-IPv4 Topology Table for AS(100)/ID(10.1.3.9) Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - reply Status, s - sia Status P 10.1.102.0/29, successors, FD is 41024000 via 10.1.103.1 (41024000/40512000), Serial0/0/0 via 10.1.203.2 (41024000/40512000), Serial0/0/1 P 10.1.1.8/30, successors, FD is 40640000 via 10.1.103.1 (40640000/128256), Serial0/0/0 P 10.1.3.0/30, successors, FD is 128256 via Connected, Loopback31 P 10.1.3.4/30, successors, FD is 128256 via Connected, Loopback35 P 10.1.3.8/30, successors, FD is 128256 via Connected, Loopback39 P 10.1.2.8/30, successors, FD is 40640000 via 10.1.203.2 (40640000/128256), Serial0/0/1 P 10.1.2.0/30, successors, FD is 40640000 via 10.1.203.2 (40640000/128256), Serial0/0/1 P 10.1.103.0/29, successors, FD is 40512000 via Connected, Serial0/0/0 P 10.1.203.0/29, successors, FD is 40512000 via Connected, Serial0/0/1 P 10.1.1.4/30, successors, FD is 40640000 via 10.1.103.1 (40640000/128256), Serial0/0/0 P 10.1.2.4/30, successors, FD is 40640000 via 10.1.203.2 (40640000/128256), Serial0/0/1 P 10.1.1.0/30, successors, FD is 40640000 via 10.1.103.1 (40640000/128256), Serial0/0/0 R3# b The most important thing is the two successor routes in the passive state on R3 R1 and R2 are both advertising their connected subnet of 10.1.102.0/30 Because both routes have the same feasible distance of 41024000, both are installed in the topology table This distance of 41024000 reflects the composite metric of more granular properties about the path to the destination network Can you view the metrics before the composite metric is computed? © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing Yes, the EIGRP route advertisements and updates indicate each of the individual path metrics that EIGRP uses These path metrics can be displayed with the show ip eigrp topology network/mask command c Use the show ip eigrp topology 10.1.102.0/29 command to view the information that EIGRP has received about the route from R1 and R2 R3# show ip eigrp topology 10.1.102.0/29 EIGRP-IPv4 Topology Entry for AS(100)/ID(10.1.3.9) for 10.1.102.0/29 State is Passive, Query origin flag is 1, Successor(s), FD is 41024000 Descriptor Blocks: 10.1.103.1 (Serial0/0/0), from 10.1.103.1, Send flag is 0x0 Composite metric is (41024000/40512000), route is Internal Vector metric: Minimum bandwidth is 64 Kbit Total delay is 40000 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is Originating router is 10.1.1.9 10.1.203.2 (Serial0/0/1), from 10.1.203.2, Send flag is 0x0 Composite metric is (41024000/40512000), route is Internal Vector metric: Minimum bandwidth is 64 Kbit Total delay is 40000 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is Originating router is 10.1.2.9 R3# The output of this command shows the following information regarding EIGRP: • The bandwidth metric represents the minimum bandwidth among all links comprising the path to the destination network • The delay metric represents the total delay over the path • The minimum MTU represents the smallest MTU along the path • If you not have full knowledge of your network, you can use the hop count information to check how many Layer devices are between the router and the destination network Step 4: Observe equal-cost load balancing EIGRP produces equal-cost load balancing to the destination network 10.1.102.0/29 from R1 Two equal-cost paths are available to this destination per the topology table output above a Use the traceroute 10.1.102.1 command to view the hops from R3 to this R1 IP address Notice that both R1 and R2 are listed as hops because there are two equal-cost paths and packets can reach this network via either link R3# traceroute 10.1.102.1 Type escape sequence to abort Tracing the route to 10.1.102.1 VRF info: (vrf in name/id, vrf out name/id) 10.1.203.2 24 msec 10.1.103.1 12 msec 10.1.203.2 24 msec R3# © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing Cisco IOS enables Cisco Express Forwarding (CEF), which, by default, performs per-destination load balancing CEF allows for very rapid switching without the need for route processing However, if you were to ping the destination network, you would not see load balancing occurring on a packet level because CEF treats the entire series of pings as one flow CEF on R3 overrides the per-packet balancing behavior of process switching with per-destination load balancing b To see the full effect of EIGRP equal-cost load balancing, temporarily disable CEF and route caching so that all IP packets are processed individually and not fast-switched by CEF R3(config)# no ip cef R3(config)# interface S0/0/0 R3(config-if)# no ip route-cache R3(config-if)# interface S0/0/1 R3(config-if)# no ip route-cache Note: Typically, you would not disable CEF in a production network It is done here only to illustrate load balancing Another way to demonstrate per-packet load balancing, that does not disable CEF, is to use the perpacket load balancing command ip load-share per-packet on outgoing interfaces S0/0/0 and S0/0/1 c Verify load balancing with the debug ip packet command, and then ping 10.1.102.1 Like any debug command, debug ip packet should be used with caution on a production network Without any ACL filtering, this command will overwhelm the router’s CPU processes in a production environment Issue the undebug all command to stop debug processing You see output similar to the following: R3# debug ip packet IP packet debugging is on R3# ping 10.1.102.1 Type escape sequence to abort Sending 5, 100-byte ICMP Echos to 10.1.102.1, timeout is seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 28/36/44 ms R3# Success rate is 100 percent (5/5), round-trip min/avg/max = 28/36/44 ms R3# *Jun 22 11:39:37.043: IP: tableid=0, s=10.1.203.3 (local), d=10.1.102.1 (Serial0/0/1), routed via RIB *Jun 22 11:39:37.043: IP: s=10.1.203.3 (local), d=10.1.102.1 (Serial0/0/1), len 100, sending *Jun 22 11:39:37.043: IP: s=10.1.203.3 (local), d=10.1.102.1 (Serial0/0/1), len 100, sending full packet *Jun 22 11:39:37.087: IP: s=10.1.102.1 (Serial0/0/0), d=10.1.203.3, len 100, input feature, MCI Check(104), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE *Jun 22 11:39:37.087: IP: tableid=0, s= R3#10.1.102.1 (Serial0/0/0), d=10.1.203.3 (Serial0/0/1), routed via RIB *Jun 22 11:39:37.087: IP: s=10.1.102.1 (Serial0/0/0), d=10.1.203.3, len 100, rcvd *Jun 22 11:39:37.087: IP: s=10.1.102.1 (Serial0/0/0), d=10.1.203.3, len 100, stop process pak for forus packet *Jun 22 11:39:37.087: IP: tableid=0, s=10.1.103.3 (local), d=10.1.102.1 (Serial0/0/0), routed via RIB *Jun 22 11:39:37.087: IP: s=10.1.103.3 (local), d=10.1.102.1 (Serial0/0/0), len 100, sending *Jun 22 11:39:37.087: IP: s=10.1.103.3 (local), R3# d=10.1.102.1 (Serial0/0/0), len 100, sending full packet *Jun 22 11:39:37.115: IP: s=10.1.102.1 (Serial0/0/0), d=10.1.103.3, len 100, input feature, MCI Check(104), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing R3# undebug all Notice that EIGRP load-balances between Serial0/0/0 (s=10.1.103.3) and Serial0/0/1 (s=10.1.203.3) This behavior is part of EIGRP It can help utilize underused links in a network, especially during periods of congestion Step 5: Analyze alternate EIGRP paths not in the topology table a Issue the show ip eigrp topology command on R3 to see successors and feasible successors for each route that R3 has learned through EIGRP R3# show ip eigrp topology EIGRP-IPv4 Topology Table for AS(100)/ID(10.1.3.9) Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - reply Status, s - sia Status P 10.1.102.0/29, successors, FD is 41024000 via 10.1.103.1 (41024000/40512000), Serial0/0/0 via 10.1.203.2 (41024000/40512000), Serial0/0/1 P 10.1.1.8/30, successors, FD is 40640000 via 10.1.103.1 (40640000/128256), Serial0/0/0 P 10.1.3.0/30, successors, FD is 128256 via Connected, Loopback31 P 10.1.3.4/30, successors, FD is 128256 via Connected, Loopback35 P 10.1.3.8/30, successors, FD is 128256 via Connected, Loopback39 P 10.1.2.8/30, successors, FD is 40640000 via 10.1.203.2 (40640000/128256), Serial0/0/1 P 10.1.2.0/30, successors, FD is 40640000 via 10.1.203.2 (40640000/128256), Serial0/0/1 P 10.1.103.0/29, successors, FD is 40512000 via Connected, Serial0/0/0 P 10.1.203.0/29, successors, FD is 40512000 via Connected, Serial0/0/1 P 10.1.1.4/30, successors, FD is 40640000 via 10.1.103.1 (40640000/128256), Serial0/0/0 P 10.1.2.4/30, successors, FD is 40640000 via 10.1.203.2 (40640000/128256), Serial0/0/1 P 10.1.1.0/30, successors, FD is 40640000 via 10.1.103.1 (40640000/128256), Serial0/0/0 R3# Perhaps you expected to see two entries to the R1 and R2 loopback networks in the R3 topology table Why is there only one entry shown in the topology table? © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page 10 of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing The reported distance of the loopback interfaces on R1 from R1 is 128256 The reported distance to the same loopback interfaces reported to R3 from R2 is 40640000 c Use the show ip eigrp topology 10.1.2.0/30 command to see the granular view of the alternate paths to 10.1.2.0, including ones with a higher reported distance than the feasible distance R3# show ip eigrp topology 10.1.2.0/30 IP-EIGRP (AS 100): Topology entry for 10.1.2.0/30 State is Passive, Query origin flag is 1, Successor(s), FD is 40640000 Routing Descriptor Blocks: 10.1.203.2 (Serial0/0/1), from 10.1.203.2, Send flag is 0x0 Composite metric is (40640000/128256), Route is Internal Vector metric: Minimum bandwidth is 64 Kbit Total delay is 25000 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is 10.1.103.1 (Serial0/0/0), from 10.1.103.1, Send flag is 0x0 Composite metric is (41152000/40640000), Route is Internal Vector metric: Minimum bandwidth is 64 Kbit Total delay is 45000 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is When using the show ip eigrp topology command, why is the route to 10.1.2.0/30 through R1 (via 10.1.103.1) not listed in the topology table? The route does not meet the feasibility condition The feasibility condition states that the reported distance (RD) must be strictly less than the feasible distance (FD) for the route to be entered into the topology table RDR1 (40640000) < FD (40640000) is false Therefore, the route is not entered into the topology table What is its reported distance from R1? RDR1 = 40640000 What is its feasible distance? © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page 12 of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing FD = 40640000 If the R2 Serial0/0/1 interface were shut down, would EIGRP route through R1 to get to 10.1.2.0/30? Why isn’t the switch to a new path a quick as it could be? Yes, but there is no feasible successor so EIGRP would need to query its neighbors R1 would detect that the link protocol is down, having no successor it goes into the active state for this route, queries its neighbors for a path and receives replies informing it of a route through R1 At this point EIGRP routing would use the new path through R1 The switch over to the path through R1 is not as quick as if R1 had a feasible successor to 10.1.2.0/30 However, as soon as R3 realizes that the link is down, it will begin to recalculate The switch will be very quick Record your answer, and then experiment by shutting down the R1 S0/0/1 interface while an extended ping is running as described below d Start a ping with a high repeat count on R3 to the R1 Serial0/0/0 interface 10.1.102.1 R3# ping 10.1.102.1 repeat 10000 e Enter interface configuration mode on R1 and shut down port Serial0/0/1, which is the direct link from R1 to R3 R1(config)# interface serial 0/0/1 R1(config-if)# shutdown f When the adjacency between R1 and R3 goes down, some pings will be lost After pings are again being successfully received, stop the ping using Ctrl+Shift+^ R3#ping 10.1.102.1 repeat 10000 Type escape sequence to abort Sending 10000, 100-byte ICMP Echos to 10.1.102.1, timeout is seconds: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!! *Jun 22 12:56:45.739: %LINK-3-UPDOWN: Interface Serial0/0/1, changed state to down!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!! *Jun 22 12:56:45.739: %DUAL-5-NBRCHANGE: EIGRP-IPv4 100: Neighbor 10.1.203.2 (Serial0/0/1) is down: interface down *Jun 22 12:56:46.739: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/1, changed state to down!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page 13 of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing ! *Jun 22 12:57:08.723: %LINK-3-UPDOWN: Interface Serial0/0/1, changed state to up *Jun 22 12:57:09.723: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/1, changed state to up!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!! *Jun 22 12:57:10.003: %DUAL-5-NBRCHANGE: EIGRP-IPv4 100: Neighbor 10.1.203.2 (Serial0/0/1) is up: new adjacency!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Success rate is 99 percent (2039/2041), round-trip min/avg/max = 24/31/104 ms R3# How many packets were dropped? In this example, two packets were dropped during the cutover Note: When examining the EIGRP reconvergence speed after deactivating the serial link between R1 and R3, the focus should not be on the count of lost ping packets but rather on the duration of connectivity loss or how long it took to perform a successful cutover The router waits for up to two seconds for each sent ICMP ECHO request to receive a reply and only then does it send another ECHO request If the router did not wait for the reply, the count of lost packets would be much higher Because two packets were lost, the cutover took approximately seconds Another factor to consider is that an interface deliberately delays the information about loss of connectivity for seconds to prevent transient link flaps (link going up and down) from introducing instability into the network If the real speed of EIGRP is to be observed, this delay can be made as short as possible using the command carrier-delay msec on all serial interfaces g Issue the no shutdown command on the R1 Serial0/0/1 interface before continuing to the next step Step 6: Observe unequal-cost load balancing Topology showing modified bandwidths as configured in step 6-b © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page 14 of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing a Review the composite metrics advertised by EIGRP using the show ip eigrp topology 10.1.2.0/30 command, R3# show ip eigrp topology 10.1.2.0/30 IP-EIGRP (AS 100): Topology entry for 10.1.2.0/30 State is Passive, Query origin flag is 1, Successor(s), FD is 40640000 Routing Descriptor Blocks: 10.1.203.2 (Serial0/0/1), from 10.1.203.2, Send flag is 0x0 Composite metric is (40640000/128256), Route is Internal Vector metric: Minimum bandwidth is 64 Kbit Total delay is 25000 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is 10.1.103.1 (Serial0/0/0), from 10.1.103.1, Send flag is 0x0 Composite metric is (41152000/40640000), Route is Internal Vector metric: Minimum bandwidth is 64 Kbit Total delay is 45000 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is The reported distance for a loopback network is higher than the feasible distance, so DUAL does not consider it a feasible successor route b To demonstrate unequal-cost load balancing in your internetwork, upgrade the path to the destination network through R1 with a higher bandwidth Change the clock rate and bandwidth on the R1, R2, and R3 serial interfaces to 128 kb/s © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page 15 of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing R1(config)# interface serial 0/0/0 R1(config-if)# bandwidth 128 R1(config-if)# clock rate 128000 R1(config-if)# interface serial 0/0/1 R1(config-if)# bandwidth 128 R2(config)# interface serial 0/0/0 R2(config-if)# bandwidth 128 R3(config)# interface serial 0/0/0 R3(config-if)# clock rate 128000 R3(config-if)# bandwidth 128 c Issue the show ip eigrp topology 10.1.2.0/30 command again on R3 to see what has changed R3# show ip eigrp topology 10.1.2.0/30 EIGRP-IPv4 Topology Entry for AS(100)/ID(10.1.3.9) for 10.1.2.0/30 State is Passive, Query origin flag is 1, Successor(s), FD is 21152000 Descriptor Blocks: 10.1.103.1 (Serial0/0/0), from 10.1.103.1, Send flag is 0x0 Composite metric is (21152000/20640000), route is Internal Vector metric: Minimum bandwidth is 128 Kbit Total delay is 45000 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is Originating router is 10.1.2.9 10.1.203.2 (Serial0/0/1), from 10.1.203.2, Send flag is 0x0 Composite metric is (40640000/128256), route is Internal Vector metric: Minimum bandwidth is 64 Kbit Total delay is 25000 microseconds Reliability is 255/255 Load is 3/255 Minimum MTU is 1500 Hop count is Originating router is 10.1.2.9 R3# After manipulating the bandwidth parameter, the preferred path for R3 to the loopback interfaces of R2 is now through R1 Even though the hop count is two and the delay through R1 is nearly twice that of the R2 path, the higher bandwidth and lower FD results in this being the preferred route Note: Hop count is only mentioned to help you visualize the two paths Hop count is not part of the composite EIGRP metric d Issue the show ip route command to verify that the preferred route to network 10.1.2.0 is through R1 via Serial0/0/0 to next hop 10.1.103.1 There is only one route to this network due to the difference in bandwidth R3# show ip route eigrp 10.0.0.0/8 is variably subnetted, 17 subnets, masks D 10.1.1.0/30 [90/20640000] via 10.1.103.1, 00:05:09, D 10.1.1.4/30 [90/20640000] via 10.1.103.1, 00:05:09, D 10.1.1.8/30 [90/20640000] via 10.1.103.1, 00:05:09, D 10.1.2.0/30 [90/21152000] via 10.1.103.1, 00:05:09, © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Serial0/0/0 Serial0/0/0 Serial0/0/0 Serial0/0/0 Page 16 of 26 CCNPv7 ROUTE D D D R3# Lab 2-1, EIGRP Load Balancing 10.1.2.4/30 [90/21152000] via 10.1.103.1, 00:05:09, Serial0/0/0 10.1.2.8/30 [90/21152000] via 10.1.103.1, 00:05:09, Serial0/0/0 10.1.102.0/29 [90/21024000] via 10.1.103.1, 00:05:09, Serial0/0/0 e The variance command is used to enable unequal-cost load balancing Setting the variance command allows you to install multiple loop-free paths with unequal costs into the routing table EIGRP will always install the successor with the best path Additional feasible successors are candidates as for unequal-cost paths to be included in the routing table These candidates must meet two conditions: • The route must be loop-free, a current feasible successor in the topology table • The metric of the route must be lower than the metric of the best route (successor), multiplied by the variance configured on the router In the previous output, R3 shows the best path for 10.1.2.0/30 through R1 via 10.1.103.1 Examining the topology table on R3, there is also a feasible successor to this network through R2 via 10.1.203.1 R3# show ip eigrp topology EIGRP-IPv4 Topology Table for AS(100)/ID(10.1.3.9) Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - reply Status, s - sia Status P 10.1.102.0/29, successors, FD is 21024000 via 10.1.103.1 (21024000/20512000), Serial0/0/0 via 10.1.203.2 (41024000/20512000), Serial0/0/1 P 10.1.1.8/30, successors, FD is 20640000 via 10.1.103.1 (20640000/128256), Serial0/0/0 P 10.1.3.0/30, successors, FD is 128256 via Connected, Loopback31 P 10.1.3.4/30, successors, FD is 128256 via Connected, Loopback35 P 10.1.3.8/30, successors, FD is 128256 via Connected, Loopback39 P 10.1.2.8/30, successors, FD is 21152000 via 10.1.103.1 (21152000/20640000), Serial0/0/0 via 10.1.203.2 (40640000/128256), Serial0/0/1 P 10.1.2.0/30, successors, FD is 21152000 via 10.1.103.1 (21152000/20640000), Serial0/0/0 via 10.1.203.2 (40640000/128256), Serial0/0/1 P 10.1.103.0/29, successors, FD is 20512000 via Connected, Serial0/0/0 P 10.1.203.0/29, successors, FD is 40512000 via Connected, Serial0/0/1 P 10.1.1.4/30, successors, FD is 20640000 via 10.1.103.1 (20640000/128256), Serial0/0/0 P 10.1.2.4/30, successors, FD is 21152000 via 10.1.103.1 (21152000/20640000), Serial0/0/0 via 10.1.203.2 (40640000/128256), Serial0/0/1 P 10.1.1.0/30, successors, FD is 20640000 via 10.1.103.1 (20640000/128256), Serial0/0/0 R3# f Issue the debug ip eigrp 100 command on R3 to show route events changing in real time Then, under the EIGRP router configuration on R3, issue the variance command, which allows unequal-cost load balancing bounded by a maximum distance of (2) × (FD), where FD represents the feasible distance for each route in the routing table Using 10.1.2.0/30 as an example, (2) x (21152000) = 42304000 The FD of the feasible successor is © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page 17 of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing 40640000 which is less that the variance-modified FD of 42304000 Therefore, the feasible successor route become an additional successor and is added to the routing table R3# debug ip eigrp 100 EIGRP-IPv4 Route Event debugging is on for AS(100) R3# conf t Enter configuration commands, one per line End with CNTL/Z R3(config)# router eigrp 100 R3(config-router)# variance R3(config-router)# *Jun 22 13:16:19.087: EIGRP-IPv4(100): table(default): route installed for 10.1.102.0/29 (90/21024000) origin(10.1.103.1) *Jun 22 13:16:19.087: EIGRP-IPv4(100): table(default): route installed for 10.1.102.0/29 (90/41024000) origin(10.1.203.2) *Jun 22 13:16:19.091: EIGRP-IPv4(100): table(default): route installed for 10.1.1.8/30 (90/20640000) origin(10.1.103.1) *Jun 22 13:16:19.091: EIGRP-IPv4(100): table(default): 10.1.1.8/30 routing table not updated thru 10.1.203.2 *Jun 22 13:16:19.091: EIGRP-IPv4 R3(config-router)#(100): table(default): route installed for 10.1.2.8/30 (90/21152000) origin(10.1.103.1) *Jun 22 13:16:19.091: EIGRP-IPv4(100): table(default): route installed for 10.1.2.8/30 (90/40640000) origin(10.1.203.2) *Jun 22 13:16:19.091: EIGRP-IPv4(100): table(default): route installed for 10.1.2.0/30 (90/21152000) origin(10.1.103.1) *Jun 22 13:16:19.091: EIGRP-IPv4(100): table(default): route installed for 10.1.2.0/30 (90/40640000) origin(10.1.203.2) *Jun 22 13:16:19.091: EIGRP-IPv4(100): table(default): 10.1 R3(config-router)#.103.0/29 routing table not updated thru 10.1.203.2 *Jun 22 13:16:19.091: EIGRP-IPv4(100): table(default): route installed for 10.1.1.4/30 (90/20640000) origin(10.1.103.1) *Jun 22 13:16:19.091: EIGRP-IPv4(100): table(default): 10.1.1.4/30 routing table not updated thru 10.1.203.2 *Jun 22 13:16:19.091: EIGRP-IPv4(100): table(default): route installed for 10.1.2.4/30 (90/21152000) origin(10.1.103.1) *Jun 22 13:16:19.091: EIGRP-IPv4(100): table(default): route installed for 10.1.2.4/30 (90/40640000) origi R3(config-router)#n(10.1.203.2) *Jun 22 13:16:19.091: EIGRP-IPv4(100): table(default): route installed for 10.1.1.0/30 (90/20640000) origin(10.1.103.1) *Jun 22 13:16:19.091: EIGRP-IPv4(100): table(default): 10.1.1.0/30 routing table not updated thru 10.1.203.2 *Jun 22 13:16:19.103: EIGRP-IPv4(100): table(default): 10.1.102.0/29 - advertise out Serial0/0/0 g Issue the show ip route command again to verify that there are now two routes to network 10.1.2.0 Notice that the two routes have different (unequal) metrics (feasible distances) R3# show ip route eigrp D D D D D 10.0.0.0/8 is variably subnetted, 17 subnets, masks 10.1.1.0/30 [90/20640000] via 10.1.103.1, 00:05:56, 10.1.1.4/30 [90/20640000] via 10.1.103.1, 00:05:56, 10.1.1.8/30 [90/20640000] via 10.1.103.1, 00:05:56, 10.1.2.0/30 [90/40640000] via 10.1.203.2, 00:05:56, [90/21152000] via 10.1.103.1, 00:05:56, 10.1.2.4/30 [90/40640000] via 10.1.203.2, 00:05:56, © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Serial0/0/0 Serial0/0/0 Serial0/0/0 Serial0/0/1 Serial0/0/0 Serial0/0/1 Page 18 of 26 CCNPv7 ROUTE D D Lab 2-1, EIGRP Load Balancing [90/21152000] via 10.1.103.1, 00:05:56, Serial0/0/0 10.1.2.8/30 [90/40640000] via 10.1.203.2, 00:05:56, Serial0/0/1 [90/21152000] via 10.1.103.1, 00:05:56, Serial0/0/0 10.1.102.0/29 [90/41024000] via 10.1.203.2, 00:05:56, Serial0/0/1 [90/21024000] via 10.1.103.1, 00:05:56, Serial0/0/0 R3# h These unequal-cost routes also show up in the EIGRP topology table as an additional successor Use the show ip eigrp topology command to verify this Notice there are two successor routes with different (unequal) feasible distances R3# show ip eigrp topology EIGRP-IPv4 Topology Table for AS(100)/ID(10.1.3.9) Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - reply Status, s - sia Status P 10.1.102.0/29, successors, FD is 21024000 via 10.1.103.1 (21024000/20512000), Serial0/0/0 via 10.1.203.2 (41024000/20512000), Serial0/0/1 P 10.1.1.8/30, successors, FD is 20640000 via 10.1.103.1 (20640000/128256), Serial0/0/0 P 10.1.3.0/30, successors, FD is 128256 via Connected, Loopback31 P 10.1.3.4/30, successors, FD is 128256 via Connected, Loopback35 P 10.1.3.8/30, successors, FD is 128256 via Connected, Loopback39 P 10.1.2.8/30, successors, FD is 21152000 via 10.1.203.2 (40640000/128256), Serial0/0/1 via 10.1.103.1 (21152000/20640000), Serial0/0/0 P 10.1.2.0/30, successors, FD is 21152000 via 10.1.203.2 (40640000/128256), Serial0/0/1 via 10.1.103.1 (21152000/20640000), Serial0/0/0 P 10.1.103.0/29, successors, FD is 20512000 via Connected, Serial0/0/0 P 10.1.203.0/29, successors, FD is 40512000 via Connected, Serial0/0/1 P 10.1.1.4/30, successors, FD is 20640000 via 10.1.103.1 (20640000/128256), Serial0/0/0 P 10.1.2.4/30, successors, FD is 21152000 via 10.1.203.2 (40640000/128256), Serial0/0/1 via 10.1.103.1 (21152000/20640000), Serial0/0/0 P 10.1.1.0/30, successors, FD is 20640000 via 10.1.103.1 (20640000/128256), Serial0/0/0 R3# i Load balancing over serial links occurs in blocks of packets, the number of which are recorded in the routing table’s detailed routing information Use the show ip route 10.1.2.0 command to get a detailed view of how traffic is shared between the two links The traffic share counters represent the ratio of traffic over the shared paths In this case the ratio is 48:25 or about 2-to-1 The path through R1, 10.1.103.1, will be sent twice as much traffic as the path through R2, 10.1.203.2 A traffic share count of on all routes indicates equal cost load balancing If the traffic share count is 0, the path is not in use R3# show ip route 10.1.2.0 Routing entry for 10.1.2.0/30 © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page 19 of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing Known via "eigrp 100", distance 90, metric 21152000, type internal Redistributing via eigrp 100 Last update from 10.1.203.2 on Serial0/0/1, 00:10:11 ago Routing Descriptor Blocks: 10.1.203.2, from 10.1.203.2, 00:10:11 ago, via Serial0/0/1 Route metric is 40640000, traffic share count is 25 Total delay is 25000 microseconds, minimum bandwidth is 64 Kbit Reliability 255/255, minimum MTU 1500 bytes Loading 3/255, Hops * 10.1.103.1, from 10.1.103.1, 00:10:11 ago, via Serial0/0/0 Route metric is 21152000, traffic share count is 48 Total delay is 45000 microseconds, minimum bandwidth is 128 Kbit Reliability 255/255, minimum MTU 1500 bytes Loading 1/255, Hops R3# j Check the actual load balancing using the debug ip packet command Ping from R3 to 10.1.2.1 with a high enough repeat count to view the load balancing over both paths In the case above, the traffic share is 25 packets routed to R2 to every 48 packets routed to R1 To filter the debug output to make it more useful, use the following extended access list R3(config)# access-list 100 permit icmp any any echo R3(config)# end R3# debug ip packet 100 IP packet debugging is on for access list 100 R3# ping 10.1.2.1 repeat 50 Type escape sequence to abort Sending 50, 100-byte ICMP Echos to 10.1.2.1, timeout is seconds: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! *Jun 22 13:48:23.598: IP: tableid=0, s=10.1.103.3 (local), d=10.1.2.1 (Serial0/0/0), routed via RIB *Jun 22 13:48:23.598: IP: s=10.1.103.3 (local), d=10.1.2.1 (Serial0/0/0), sending *Jun 22 13:48:23.598: IP: s=10.1.103.3 (local), d=10.1.2.1 (Serial0/0/0), sending full packet *Jun 22 13:48:23.626: IP: tableid=0, s=10.1.103.3 (local), d=10.1.2.1 (Serial0/0/0), routed via RIB *Jun 22 13:48:23.626: IP: s=10.1.103.3 (local), d=10.1.2.1 (Serial0/0/0), sending !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! *Jun 22 13:48:23.626: IP: s=10.1.103.3 (local), d=10.1.2.1 (Serial0/0/0), sending full packet *Jun 22 13:48:23.654: IP: tableid=0, s=10.1.103.3 (local), d=10.1.2.1 (Serial0/0/0), routed via RIB *Jun 22 13:48:23.654: IP: s=10.1.103.3 (local), d=10.1.2.1 (Serial0/0/0), sending *Jun 22 13:48:23.654: IP: s=10.1.103.3 (local), d=10.1.2.1 (Serial0/0/0), sending full packet ! len 100, len 100, len 100, len 100, len 100, len 100, R3 just switched to load-share the outbound ICMP packets to Serial0/0/1 ! *Jun 22 13:48:24.954: IP: s=10.1.203.3 (local), d=10.1.2.1 (Serial0/0/1), len 100, sending © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page 20 of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing *Jun 22 13:48:24.954: IP: s=10.1.203.3 (local), d=10.1.2.1 sending full packet *Jun 22 13:48:24.982: IP: tableid=0, s=10.1.203.3 (local), (Serial0/0/1), routed via RIB *Jun 22 13:48:24.982: IP: s=10.1.203.3 (local), d=10.1.2.1 sending *Jun 22 13:48:24.982: IP: s=10.1.203.3 (local), d=10.1.2.1 R3#), len 100, sending full packet R3# (Serial0/0/1), len 100, d=10.1.2.1 (Serial0/0/1), len 100, (Serial0/0/1 Note: If a deliberate metric manipulation is necessary on a router to force it to prefer one interface over another for EIGRP-discovered routes, it is recommended to use the interface-level command "delay" for these purposes While the "bandwidth" command can also be used to influence the metrics of EIGRP-discovered routes through a particular interface, it is discouraged because the "bandwidth" will also influence the amount of bandwidth reserved for EIGRP packets and other IOS subsystems as well The "delay" parameter specifies the value of the interface delay that is used exclusively by EIGRP to perform metric calculations and does not influence any other area of IOS operation k Issue the show ip protocols command will verify the variance parameter and the number of maximum paths used by EIGRP By default, EIGRP will use a maximum of paths for load balancing This value can be changed using the maximum-path EIGRP configuration command R3# show ip protocols *** IP Routing is NSF aware *** Routing Protocol is "application" Sending updates every seconds Invalid after seconds, hold down 0, flushed after Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Maximum path: 32 Routing for Networks: Routing Information Sources: Gateway Distance Last Update Distance: (default is 4) Routing Protocol is "eigrp 100" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Default networks flagged in outgoing updates Default networks accepted from incoming updates EIGRP-IPv4 Protocol for AS(100) Metric weight K1=1, K2=0, K3=1, K4=0, K5=0 NSF-aware route hold timer is 240 Router-ID: 10.1.3.9 Topology : (base) Active Timer: Distance: internal 90 external 170 Maximum path: Maximum hopcount 100 Maximum metric variance Automatic Summarization: disabled Maximum path: Routing for Networks: 10.0.0.0 Routing Information Sources: Gateway Distance Last Update © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page 21 of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing 10.1.103.1 90 00:39:03 10.1.203.2 90 00:39:03 Distance: internal 90 external 170 R3# © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page 22 of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing Device Configurations (Instructor version) Initial Configurations Router R1 hostname R1 ! interface Loopback11 ip address 10.1.1.1 255.255.255.252 ! interface Loopback15 ip address 10.1.1.5 255.255.255.252 ! interface Loopback19 ip address 10.1.1.9 255.255.255.252 ! interface Serial0/0/0 description R1 >R2 bandwidth 64 ip address 10.1.102.1 255.255.255.248 clock rate 64000 no shut ! interface Serial0/0/1 description R1 >R3 bandwidth 64 ip address 10.1.103.1 255.255.255.248 no shut ! end Router R2 hostname R2 ! interface Loopback21 ip address 10.1.2.1 255.255.255.252 ! interface Loopback25 ip address 10.1.2.5 255.255.255.252 ! interface Loopback29 ip address 10.1.2.9 255.255.255.252 ! interface Serial0/0/0 description R2 >R1 bandwidth 64 ip address 10.1.102.2 255.255.255.248 no shut ! interface Serial0/0/1 description R2 >R3 bandwidth 64 ip address 10.1.203.2 255.255.255.248 clock rate 64000 © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page 23 of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing no shut ! end Router R3 ! hostname R3 ! interface Loopback31 ip address 10.1.3.1 255.255.255.252 ! interface Loopback35 ip address 10.1.3.5 255.255.255.252 ! interface Loopback39 ip address 10.1.3.9 255.255.255.252 ! interface Serial0/0/0 description R3 >R1 bandwidth 64 ip address 10.1.103.3 255.255.255.248 clock rate 64000 no shut ! interface Serial0/0/1 description R3 >R2 bandwidth 64 ip address 10.1.203.3 255.255.255.248 no shut ! end Final Configurations Router R1 ! hostname R1 ! interface Loopback11 ip address 10.1.1.1 255.255.255.252 ! interface Loopback15 ip address 10.1.1.5 255.255.255.252 ! interface Loopback19 ip address 10.1.1.9 255.255.255.252 ! interface Serial0/0/0 description R1 >R2 bandwidth 128 ip address 10.1.102.1 255.255.255.248 clock rate 128000 no shutdown ! © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page 24 of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing interface Serial0/0/1 description R1 >R3 bandwidth 128 ip address 10.1.103.1 255.255.255.248 no shutdown ! router eigrp 100 network 10.0.0.0 ! end Router R2 hostname R2 ! interface Loopback21 ip address 10.1.2.1 255.255.255.252 ! interface Loopback25 ip address 10.1.2.5 255.255.255.252 ! interface Loopback29 ip address 10.1.2.9 255.255.255.252 ! interface Serial0/0/0 description R2 >R1 bandwidth 128 ip address 10.1.102.2 255.255.255.248 no shutdown ! interface Serial0/0/1 description R2 >R3 bandwidth 64 ip address 10.1.203.2 255.255.255.248 no shutdown ! router eigrp 100 network 10.0.0.0 ! end Router R3 hostname R3 ! interface Loopback31 ip address 10.1.3.1 255.255.255.252 ! interface Loopback35 ip address 10.1.3.5 255.255.255.252 ! interface Loopback39 ip address 10.1.3.9 255.255.255.252 ! interface Serial0/0/0 description R3 >R1 © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page 25 of 26 CCNPv7 ROUTE Lab 2-1, EIGRP Load Balancing bandwidth 128 ip address 10.1.103.3 255.255.255.248 clock rate 128000 no shutdown ! interface Serial0/0/1 description R3 >R2 bandwidth 64 ip address 10.1.203.3 255.255.255.248 no shutdown ! router eigrp 100 variance network 10.0.0.0 ! access-list 100 permit icmp any any echo ! end © 2014 Cisco and/or its affiliates All rights reserved This document is Cisco Public Page 26 of 26 ... Address/Mask R1 Loopback 11 10 .1. 1 .1/ 30 R1 Loopback15 10 .1. 1.5/30 R1 Loopback19 10 .1. 1.9/30 R2 Loopback 21 10 .1. 2 .1/ 30 R2 Loopback25 10 .1. 2.5/30 R2 Loopback29 10 .1. 2.9/30 R3 Loopback 31 10 .1. 3 .1/ 30 R3... eigrp 10 .1. 102.0/29 (0x0) : via 10 .1. 103 .1 Se0/0/0 10 48578 *Jun 22 11 :06 :19 .055: RT: add 10 .1. 102.0/29 via 10 .1. 103 .1, eigrp metric [90/ 410 24000] *Jun 22 11 :06 :19 .055: RT: updating eigrp 10 .1. 1.0/30... eigrp 10 .1. 1.4/30 (0x0) : via 10 .1. 103 .1 Se0/0/0 10 48578 *Jun 22 11 :06 :19 .055: RT: add 10 .1. 1.4/30 via 10 .1. 103 .1, eigrp metric [90/40640000] *Jun 22 11 :06 :19 .055: RT: updating eigrp 10 .1. 1.8/30